2017-04-02 22:49 GMT+08:00 Steven Liu <l...@chinaffmpeg.org>:
> Use AVBprint to implementing av_strreplace
>
> Signed-off-by: Steven Liu <l...@chinaffmpeg.org>
> ---
> libavutil/avstring.c | 74 ++++++------------------------
> ----------------------
> 1 file changed, 8 insertions(+), 66 deletions(-)
>
> diff --git a/libavutil/avstring.c b/libavutil/avstring.c
> index 52e6e6cd13..55f3bee94c 100644
> --- a/libavutil/avstring.c
> +++ b/libavutil/avstring.c
> @@ -233,78 +233,20 @@ int av_strncasecmp(const char *a, const char *b,
> size_t n)
>
> char *av_strreplace(const char *str, const char *from, const char *to)
> {
> - /* Adjust each of the below values to suit your needs. */
> - /* Increment positions cache size initially by this number. */
> - size_t cache_sz_inc = 16;
> - /* Thereafter, each time capacity needs to be increased,
> - * multiply the increment by this factor. */
> - const size_t cache_sz_inc_factor = 3;
> - /* But never increment capacity by more than this number. */
> - const size_t cache_sz_inc_max = 1048576;
> -
> - char *pret, *ret = NULL;
> + char *ret = NULL;
> const char *pstr2, *pstr = str;
> - size_t i, count = 0;
> - uintptr_t *pos_cache_tmp, *pos_cache = NULL;
> - size_t cache_sz = 0;
> - size_t cpylen, orglen, retlen, tolen, fromlen = strlen(from);
> + size_t tolen = strlen(to), fromlen = strlen(from);
> + AVBPrint pbuf;
>
> - /* Find all matches and cache their positions. */
> + av_bprint_init(&pbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
> while ((pstr2 = av_stristr(pstr, from))) {
> - count++;
> - /* Increase the cache size when necessary. */
> - if (cache_sz < count) {
> - cache_sz += cache_sz_inc;
> - pos_cache_tmp = av_realloc(pos_cache, sizeof(*pos_cache) *
> cache_sz);
> - if (!pos_cache_tmp) {
> - goto end_strreplace;
> - } else pos_cache = pos_cache_tmp;
> - cache_sz_inc *= cache_sz_inc_factor;
> - if (cache_sz_inc > cache_sz_inc_max) {
> - cache_sz_inc = cache_sz_inc_max;
> - }
> - }
> -
> - pos_cache[count-1] = pstr2 - str;
> + av_bprint_append_data(&pbuf, pstr, pstr2 - pstr);
> pstr = pstr2 + fromlen;
> + av_bprint_append_data(&pbuf, to, tolen);
> }
> - orglen = pstr - str + strlen(pstr);
> - /* Allocate memory for the post-replacement string. */
> - if (count > 0) {
> - tolen = strlen(to);
> - retlen = orglen + (tolen - fromlen) * count;
> - } else {
> - retlen = orglen;
> - }
> - ret = av_malloc(retlen + 1);
> - if (!ret) {
> - goto end_strreplace;
> - }
> -
> - if (!count) {
> - /* If no matches, then just duplicate the string. */
> - av_strlcpy(ret, str, retlen + 1);
> - } else {
> - /* Otherwise, duplicate the string whilst performing
> - * the replacements using the position cache. */
> - pret = ret;
> - memcpy(pret, str, pos_cache[0]);
> - pret += pos_cache[0];
> - for (i = 0; i < count; i++) {
> - memcpy(pret, to, tolen);
> - pret += tolen;
> - pstr = str + pos_cache[i] + fromlen;
> - cpylen = (i == count-1 ? orglen : pos_cache[i+1]) -
> pos_cache[i] - fromlen;
> - memcpy(pret, pstr, cpylen);
> - pret += cpylen;
> - }
> - ret[retlen] = '\0';
> - }
> + av_bprint_append_data(&pbuf, pstr, strlen(pstr));
> + av_bprint_finalize(&pbuf, &ret);
>
> -end_strreplace:
> - /* Free the cache and return the post-replacement string,
> - * which will be NULL in the event of an error. */
> - av_free(pos_cache);
> return ret;
> }
>
> --
> 2.11.0 (Apple Git-81)
>
>
>
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> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
I have implementation the av_strreplace use AVBprint, the API context now
is:
char *av_strreplace(const char *str, const char *from, const char *to)
{
char *ret = NULL;
const char *pstr2, *pstr = str;
size_t tolen = strlen(to), fromlen = strlen(from);
AVBPrint pbuf;
av_bprint_init(&pbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
while ((pstr2 = av_stristr(pstr, from))) {
av_bprint_append_data(&pbuf, pstr, pstr2 - pstr);
pstr = pstr2 + fromlen;
av_bprint_append_data(&pbuf, to, tolen);
}
av_bprint_append_data(&pbuf, pstr, strlen(pstr));
av_bprint_finalize(&pbuf, &ret);
return ret;
}
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